138151878421 has 2 divisors, whose sum is σ = 138151878422. Its totient is φ = 138151878420.

The previous prime is 138151878409. The next prime is 138151878427. The reversal of 138151878421 is 124878151831.

138151878421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 100549239025 + 37602639396 = 317095^2 + 193914^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138151878421 is a prime.

It is a super-2 number, since 2×138151878421² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138151878427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69075939210 + 69075939211.

It is an arithmetic number, because the mean of its divisors is an integer number (69075939211).

Almost surely, 2^138151878421 is an apocalyptic number.

It is an amenable number.

138151878421 is a deficient number, since it is larger than the sum of its proper divisors (1).

138151878421 is an equidigital number, since it uses as much as digits as its factorization.

138151878421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 430080, while the sum is 49.

The spelling of 138151878421 in words is "one hundred thirty-eight billion, one hundred fifty-one million, eight hundred seventy-eight thousand, four hundred twenty-one".